ya the hydor theos are amazing. i have 3 now and will be changing all of my heaters out to these once, they are adjustable, low wattage. (i have the 25 watt ones) and reliable. you can use the 25 watt ones in small tanks and critter keepers

I use Aqueon 50 watt in my 5 gallon tanks and they're holding up great. What size tank is VP in?

VP's in a one-gallon bowl currently. I tried him in the 10-gallon, but he was moody and didn't care for it. In the one-gallon he flits everywhere and fans out to his full colours. My aim for him is to find a two- or three-gallon bowlish glass container for him, see if he likes it.

I don't think the Aqueon will fit in anything less than 5 gals so look into the hydor first. I have a boy hat doesn't seem to like anything more than 3 gallons. I'm hoping to find an inexpensive one second hand. Right now he's in a 10 gallon divided and wot stop being his tail. When there were 3 boys in there he did better but now there are only two he's freaking out. Bettas are nuts LoL!